Full list of all 18 Costume Quest 2 achievements worth 1,000 gamerscore. It takes around 8-10 hours to unlock all of the achievements on Xbox One.
Tried every Creepy Treat Card in combat
Completed all quests in the game
Used the clown horn 1000 times
Restored the timeline to save Halloween
Finish the game having fought every battle with Candy Corn in your party
Used every costume special in combat
Found the Solar System
Mastered all combat techniques from Corvus
Collected all Creepy Treat Cards
Got the liberty kids to bust a move
Defeated Ophirion
Found the Wolfman
Used the Pterodactyl Costume to flap 10 flappy things
Upgraded 3 costumes
Tried on 5 different costumes
Defeated Kronoculus and his Kronys
Bashed 10 Monster Patrols
Collected over 4 thousand candies